ABSTRACT Extra Innings: Using Serious Gaming & the Science of Baseball to Teach Science & Mathematics Due to the rapid advances in science, technology, engineering, and mathematics (STEM), the United States has been at the forefront of innovation and technology development in the health and biomedical fields. However, these continuing advances are in jeopardy as there is a growing national shortage of trained STEM workers. While the need for a STEM literate public and STEM workforce grows the education system has not been kept pace with STEM achievement and persistence and U.S. students consistently rank near the bottom of highly developed countries in mathematics and science. Reaching students by middle school is critical for setting them on the pathway to a STEM career, including those in the health research and biomedical fields. To encourage interest in STEM topics and ultimately draw more young people, particularly diverse youth, to STEM and health- related careers youth need learning opportunities that provide motivation by building on their current interests and providing real-word examples and experiences requiring context specific scientific inquiry. This project addresses these critical needs by creating Extra Innings, a serious gaming app that integrates the concepts of and complements a proven STEM curriculum, the Arizona Diamondbacks/Science of Sports Science of Baseball, developed for use with middle school students, that is aligned with the Common Core standards, National Science Education Standards, and Next Generation Science Standards. This game-delivered STEM curriculum will leverage the widespread interest in sports and video games to expand STEM learning opportunities for and motivate young students at a critical age when they are making decisions about their interest in STEM. The project is proposing to complete development of a mobile app-based serious game with a series of mini-games, each providing experiential learning around a baseball and math, science, or health concept. For example, students learn about physiology and the connection between the brain, eyes, and nervous system through testing their reaction time at fielding a baseball as the ball appears on the screen. Users also can explore a realistic virtual environment, based on an actual MLB stadium, and can interact with those involved in STEM related professions within baseball such as physical therapists and team doctors. In Phase I the prototype mobile game was successfully developed with three mini-games based on extensive formative research, and was pilot tested with diverse youth. Results showed the game was successful in increasing STEM knowledge and attitudes. This Phase II project will complete the game development with nearly 20 educational challenges, motivating prizes, ?just for fun? mini-games, and will produce iOS, Android, and virtual reality versions of the game. In addition the project will conduct a rigorous evaluation and establish the commercial model which includes purchase and sponsorship by Major League Baseball and its franchises, as was the case with the original in-person curriculum.